Air curtain structure

ABSTRACT

An air curtain structure for providing a flow of air across an access opening to a building or the like and comprising an enclosure adjacent the upper end of the opening and a pair of downwardly extending support columns arranged adjacent the sides of the opening and defining a pair of opposed air discharge slots; the enclosure being provided with a pair of heat exchanger coil assemblies adapted to condition air preparatory to the same being communicated to the support columns; at least one air blower mechanism for forcing air in heat transfer relation with the coil assemblies, and a pair of air inlet assemblies, one of which is adapted to induct air from the interior of the building into the enclosure and the other of which is adapted to induct fresh outside air from the exterior of the building into the enclosure, with the air intake assemblies being provided with closure means for selectively opening and closing the same, whereby to permit either the induction of fresh outside air and/or the recirculation of air inside the building through the heat exchanger coil assemblies.

United States Patent [191 Henson [54] AIR CURTAIN STRUCTURE [75] Inventor: Artel R. Henson, Pontiac, Mich.

[73] Assignee: Disco Engineering, Inc., Detroit,

Mich.

[22] Filed: Feb. 12, 1970 21 Appl. No.: 10,812

[ 52] US. Cl. ..98/36, 165/59 [51] Int. Cl. ..F24f 9/00 [58] Field of Search 98/36, 16, 38 E, 38 El; 165/59 [56] References Cited UNITED STATES PATENTS 3,608,468 9/1971 McClurkin "98/36 2,331,691 lO/1943 Hubbard ..98/38 E 2,135,461 11/1938 Woolley ...98/38 El 2,317,104 4/1943 Moore ...98/38 El 2,763,195 9/1956 Caldwell ...98/36 X 3,308,740 3/1967 Henson et al. ..98/36 2,593,702 4/1952 Schneible ..98/36 2,150,252 3/1939 Shure ..98/36 2,855,762 10/1958 Zehnder ....98/36 X 3,331,303 7/1967 Gladd ..98/36 3,405,758 10/1968 Walker ....98/38 El 2,775,187 12/1956 McClurkin ..98/36 Feb. 13, 1973 Primary ExaminerW illiam E. Wayner Attorney-Hamess, Dickey & Pierce [5 7 ABSTRACT An air curtain structure for providing a flow of air across an access opening to a building or the like and comprising an enclosure adjacent the upper end of the opening and a pair of downwardly extending support columns arranged adjacent the sides of the opening and defining a pair of opposed air discharge slots; the enclosure being provided with a pair of heat exchanger coil assemblies adapted to condition air preparatory to the same being communicated to the support columns; at least one air blower mechanism for forcing air in heat transfer relation with the coil assemblies, arid a pair of air inlet assemblies, one of which is adapted to induct air from the interior of the building into the enclosure and the other of which is adapted to induct fresh outside air from the exterior of the building into the enclosure, with the air intake as semblies being provided with closure means for selectively opening and closing the same, whereby to permit either the induction of fresh outside air and/or the recirculation of air inside the building through the heat exchanger coil assemblies.

17 Claims, 9 Drawing Figures PAIENTEDFEB13 I975 3,715,968

sum 10F 2 INVENTOR.

PATENTEDFEB 1 3 1915 3 7 1 5 968 sum 2 OF 2 INVENTOR.

1 m CURTAIN STRUCTURE BACKGROUND OF THE INVENTION Generally speaking, the present invention is directed toward a new and improved air curtain structure which is adapted to utilize either or both of two different air sources in order to provide a flow of air across an access opening to a building or the like whereby to create an air curtain thereacross. More particularly, the present invention is directed toward a novel air curtain structure which is designed such that fresh outside air may be inducted into the structure and thereafter be discharged across the opening to provide the desired air curtain or, alternatively, the air source for the air curtain may consist of air already within the building I and which is recirculated through the air curtain structure and discharged in the form of an air curtain.

The air curtain structure of the present invention includes in part a pair of heat exchanger coil assemblies which, in the broadest sense, are adapted to condition air discharged in the form of an air curtain. Such air conditioning may consist of heating, cooling or otherwise changing the temperature, content, etc. of the air in order to provide for optimum environmental conditioning of the building. The heat exchanger coil assemblies of the present invention-are associated with a pair of air inlet assemblies, one of which is adapted to induct fresh outside air into the air curtain structure and the other of which is adapted to induct air already within the building into the structure. A pair of blower assemblies are also provided in the air curtain structure and are adapted to function in inducting air through one or more of the aforementioned air intake assemblies and thereafter forcing said air through the heat exchanger coil assemblies from where said air is subsequently discharged across the access opening of the building to provide the desired air curtain effect.

In accordance with the present invention, the air intake assemblies are adapted to have operatively associated therewith means for selectively opening and closing the same whereby an operator may control whether or not fresh outside air and/or inside air is inducted into the structure in order to provide air for the air curtain. Such closure means is preferably provided by a louver arrangement which may be simply opened and closed in a manner well known in the art. Additionally, the air intake assemblies areprovided with a suitable filtering media for purposes of filtering the air which is subsequently discharged from the structure to provide the air curtain.

A particular feature of the present invention resides in the universality of application thereof due to the fact that either fresh outside air or air already within the building, or any desired combination thereof, may be used as a source of air for the air curtain. Additionally, in such cases where the air curtain structure of the present invention is associated with a permanent type overhead closure door or the like, the air curtain structure of the present invention may be used for recirculating and heating and/or cooling the air within the building during such time as the closure door may be temporarily closed, such as, for example, during periods of non-use of the building. Thus, the present invention not only provides a means for providing an air curtain but also a means forsupplementing or constituting the entire heating and/or cooling system for a building.

. 2 SUMMARY OF THE INVENTION This invention relates generally to air curtain structures and, more particularly, to a new and improved air curtain structure which is adapted to use either fresh outside air or air already within an associated building as a source of air for the air curtain.

It is accordingly a general object of the present invention to provide a new and improved air curtain structure.

It is a more particular object of the present invention to provide an air curtain structure of the above character which is adapted to utilize either or both fresh outside air or air already within a building as a source of air for the air curtain.

It is another object of the present invention to provide a new and improved air curtain structure of the above described type which includes a pair of heat exchanger coil assemblies for conditioning the air discharged therefrom.

It is another object of the present invention to provide an air curtain structure of the above described type which includes a pair of air intake assemblies communicable with the interior and exterior of the associated building and which are provided with closure means for selectively opening and closing an air path into the air curtain structure.

It is yet another object of the present invention to provide an air curtain structure of the above described type which will find universality of application.

It is another object of the present invention to provide an air curtain structure which is adapted to supplement or constitute the entire air heating or cooling means for the associated building.

It is still another object of the present invention to provide an air curtain structure of the above character which is of a relatively simple design, is economical to manufacture and easy to assemble and maintain.

Other objects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view of the air curtain structure of the present invention;

FIG. 2 is a cross-sectional view taken substantially along the line 2-2 of FIG. 1;

FIG. 3 is an enlarged fragmentary elevated perspective view of a portion of the structure shown in FIG. 2, as taken in the direction of the arrow 3 thereof;

FIG. 4 is a cross-sectional view takensubstantially along the line 4-4 of FIG. 3;

FIG. 5 is an enlarged cross-sectional view taken substantially along the line 5-5 of FIG. 2',

FIG. 6 is a side elevational view of the air curtain structure shown in FIG. 1;

FIG. 7 is an enlarged crosssectional view taken substantially along the line 7 -7 of FIG. 6;

FIG. 8 is a cross-sectional view similar to FIG. 2 of the air curtain structure of the present invention and illustrates a modification in the air flow control means incorporated therein, and

FIG. 9 is an enlarged fragmentary cross-sectional view taken substantially along the line 9-9 of FIG. 8.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT For purposes of clarity of description, the term conditioning of air or air conditioning" or derivatives thereof, as used herein will have reference to any suitable type of apparatus which is adapted to function in heating or cooling a source of air supplied thereto. While the present invention is particularly shown as having the air conditioning apparatus thereof comprising an air heating device, as opposed to an air cooling apparatus, it is to be understood that the present invention encompasses either the heating or cooling of air as required by the building with which the air curtain structure of the present invention is operatively associated.

Referring now in detail to the drawings and in particular to FIGS. 1 and 2, an apparatus or structure for providing an air curtain, herein generally designated by the numeral 10, in accordance with an exemplary embodiment of the present invention, is shown in operative association with a building 12 having an end or side wall 14. The building 12 may be of any suitable type, such as, for example, an automotive washing facility, with the wall 14 defining a vehicular access opening 16 defined by a pair of generally vertically extending spaced parallel sides 18 and 20 and a generally horizontally extending top or upper side 22. Generally speaking, the air curtain structure is adapted to provide a flow of air across the opening 16, whereby to selectively control the temperature interiorly of the building 12 and prevent the interior of the building 12 from being exposed to undesirable exterior or outside environmental elements, such as rain, snow or other types of inclement weather conditions, as will hereinafter be described in detail.

the air curtain structure 10 comprises an upper intermediate enclosure or housing 24 which preferably extends the entire distance across the opening 16 adjacent the upper side 22 thereof. The enclosure 24 defines an elongated internal chamber 26 and is adapted to be operatively supported upon a pair of downwardly extending support columns 28 and 30 which are arranged adjacent the lateral sides 18 and of the opening 16, as illustrated in FIG. 1. The support columns 28, 30 are generally rectangular in shape, as best seen in FIG. 7, and define a pair of air exhaust or discharge slots 32 which extend substantially the length of the columns 28, 30. The slots 32 are formed by inwardly disposed walls 34 and 36, the latter of which, in part, provides a box-like reinforcing structure 38. The slot forming walls 34, 36 project sufficiently into the support columns 28, 30 to provide some restriction of the air to be exhausted through the slots 32 in order to achieve optimum discharge velocity of the air. The columns 28, 30 are formed with recessed or stepped shoulder areas 40 which, together with adding to the structural strength of the columns 28, 30 enable an overhead door track (not shown) to be mounted upon or adjacent the columns, whereby to permit a permanent closure door (not shown) to be associated with the structure 10 for use during such time as it is desired to have the openings 16 closed. If desired, a suitable drop screen 41 of suitable construction may be pro vided between the support columns 28, 30 subjacent the overhead enclosure 24 in order to reduce the open arch area defined between the columns 28, 30 and to cooperate with the associated closure door to provide for a permanent closure for the opening 16.

Referring now in detail to the construction of the overhead enclosure 24, as best seen in FIGS. 2 and 3, the enclosure 24 comprises a pair of laterally spaced end walls 42 and 44, and top and bottom walls 46 and 48, respectively, the latter of which is provided with suitable openings 49 which are communicable with the interior of the support columns 28, 30. The enclosure 24 also comprises inner and outer sides or walls 50 and 52, the former of which is exposed to the interior of the building 12 and the latter of which is exposed to the exterior of the building 12 and is provided with a pair of laterally spaced access doors 54 which may be selectively opened to provide for access to the chamber 26, i.e., access to the contents of the enclosure 24.

As best illustrated in FIGS. 2 and 5, disposed within the interior of the enclosure 24 is a pair of air conditioning devices which are shown herein as comprising a pair of heat exchanger coil assemblies, generally designated 56, adapted for the heating of air communicated into the interior of the chamber 26. The assemblies 56 may be and preferably are identical in construction and are disposed within the chamber 26 in generally spaced, parallel vertically upright relation to one another, with the assemblies 56 lying in planes which are angularly offset somewhat from a lateral plane extending the length of the enclosure 24, as will be seen in FIG. 2. The assemblies 56 divide the interior of the chamber 26 into three generally equal volume compartments 58, 60 and 62, with the compartments 58 and 62 being communicable with the interiors of the support columns 28 and 30, and hence with the slots 32 formed therein.

As best illustrated in FIG. 5, each of the assemblies 56 comprises a generally upright intake manifold 64 at one end thereof, a cross manifold 66 at the opposite end thereof and a plurality of conduits or pipes 70 extending therebetween, with the conduits 70 cooperating with a plurality of heat conductive fins or the like, generally designated 71. The manifold 64 is adapted to be communicable via suitable inlet and outlet conduits 72 and 74, respectively, with a suitable source of hot water, such as is shown schematically in FIG. 2 as comprising a hot water heater 76, a suitable recirculating water pump or the like 78 and an expansion tank 80. As will be apparent, each of the assemblies 56 may be provided with its own independent source of hot water, or alternatively, both of the assemblies 56 may be connected to the same source, depending upon the capacity thereof.

Disposed on the inner and outer sides of the air curtain structure 10 is a pair of air inlet assemblies, generally designated 82 and 84, which are adapted to induct air interiorly of the chamber 26, and more particularly, into the compartment 60 thereof. As best seen in FIGS. 2 through 4, the air inlet assemblies 82, 84 are provided on the inner and outer side walls 50 and 52 of the enclosure 24 approximately midway between the laterally opposite ends thereof so as to be aligned with the compartment 60. Each of the assemblies 82, 84, as shown in FIG. 4, comprises a generally rectangularshaped enclosure or housing 86 which projects perpendicularly outwardly from the associated side wall of the enclosure 24. Disposed within each of the housings 86 is a plurality of horizontally extending, spaced parallel louvers 88 which are conventionally mounted on suitable cross rods or the like 90 in a manner so as to be pivotable or otherwise movable between positions opening and closing air flow paths 92 between the interior and the exterior of the building 12 and the interior of the compartment 60. The louvers 88 of each of the assemblies 82, 84 may be operatively associated with any suitable control mechanism (not shown) for opening and closing the flow paths 92 so as to selectively control the quantity of air inducted into the compartment 60, as will be apparent. Disposed at one end of each of the housings 86 is an elongated, vertically disposed slot 94 which is aligned with a pair of horizontally extending, vertically spaced tracks or guide members 96 and 98 that are adapted to removably support suitable filter elements or the like, generally designated by the numeral 100. It will be seen that air inducted through the inlet assemblies 82, 84 must pass through the filter elements 100 prior to entering the compartment 60 so that the air is properly filtered before it is discharged through the slots 32 of the support columns 28, 30. Additionally, it will be seen that the filter elements 100 are conveniently removable from the assemblies 82, 84 in order to provide for cleaning and/or replacement thereof.

Disposed within each of the compartments 58 and 62 of the enclosure 24 is an air blower mechanism, generally designated 102, which is adapted to be actuated by an associated drive motor or the like 104 via a suitable drive belt 106 which drivingly connects a drive shaft 108 of the motor 104 with a drive shaft 110 of the blower mechanism. The details of the construction and operation of the blower mechanisms 102 and associated drive motors 104 will be apparent to those skilled in the art and hence a detailed description thereof will be omitted for purposes of simplifying the instant disclosure, it being sufiicient to mention that the blower mechanisms 102 in the respective compartments 58, 62 are adapted to independently induct air through either of the air inlet assemblies 82, 84 and draw said air through the adjacent of the heat exchanger coil assemblies 56 and then force such air downwardly through the associated support columns 28, 30 for use in producing the desired air curtain.

In operation of the air curtain structure of the present invention, assuming the initial conditions that the associated source of hot water for the assemblies 56 is operating, and further assuming that the air inlet assemblies 82 and 84 are open, energization of the blower mechanisms 102 in the compartments 58 and 62 will cause air to be inducted from the exterior and the interior of the building 12 through the inlet assemblies 84 and 82, respectively, as indicated by the solid and dotted line arrows shown in FIG. 2. This air will be inducted through the compartment 60 and thereafter will be drawn through the intricacies in the heat exchanger coil assemblies 56 and into thecompartments 58 and 62, thereby being heated when passing in heat transfer relation with the assemblies 56. Thereafter, the blower mechanisms 102 will force the air within the compartments 58 and 62 downwardly through the support columns 28 and 30, whereby such 6 air will be discharged laterally inwardly through the slots 32, as shown by the arrows in FIG. 1, with the result that an effective heated air curtain is provided across the opening 16.

In accordance with the present invention, one of the other of the air inlet assemblies 82 or 84 may be selectively closed, whereby the air supply for the air curtain will be inducted through the remaining open inlet assemblies 82 or 84. For example, if it is desired to utilize fresh outside air for the air curtain, and if it is desired to pressurize the interior of the building 12, Le, add a greater quantity of air to the interior of the building 12 than that which is normally exhausted, the inlet assembly 82 may be closed. When this occurs, all of the air inducted into the air curtain structure 10 will be inducted through the inlet assembly 84 exposed to the exterior of the building so that fresh outside air will be used for the air curtain. On the other hand, if it is desired to use or recirculate the air within the building 12 for the air curtain, for example, as might be the case when the associated permanent overhead closure door is closed and the air curtain structure is used to supplement the means for heating the interior of the building 12, the outer air inlet assembly 84 could be closed. When this is done, the air for the air curtain system is inducted through the inlet assembly 82, as indicated by the dotted arrows in FIG. 2, which air is subsequently passed through the heat exchanger coil assemblies 56 where this air is heated and then discharged through the slots 32 in the support columns 28 and 30. Thus, the air curtain is made up entirely of air originally within the interior of the building 12, with the result that such air is merelyrecirculated within the building 12 and as it is recirculated through the air curtain structure 10, it is heated (and filtered) some predetermined amount in order to effect heating of the building.

It will be appreciated, of course, that instead of one or the other of the air inlet assemblies 82 or 84 being entirely closed and the other of said assemblies 82 or 84 being entirely opened, some combination thereof may be desired in order to provide the desired amount of fresh outside air for supplementing the air originally in the building 12, and. this may be readily accomplished through proper adjustment of the louvers 88 of the air inlet assemblies 82, 84. Additionally, it will be appreciated that instead of heating the air, the heat exchanger coil assemblies could be constructed in a manner so as to lower the temperature of the air passing therethrough, thus providing a means for cooling the interior of the building 12, as was hereinbefore explained.

Referring now to FIGS. 8 and 9, the air curtain structure 10 of the present invention is shown in a slightly modified form wherein a partition assembly, generally designated 112, is provided interiorly of the compartment 60. The assembly 1 12 extends diagonally between the opposite ends of the coil assemblies 56 and divides the interior of the compartment 60 into a pair of separated compartments 60a and 60b. As illustrated in FIG. 8, the compartment 60a is communicable with the interior of the associated building 12 via the inlet assembly 82, while the compartment 60b is communicable with the exterior of the building 12 via the inlet assembly 84. The assembly 112 may be and preferably is provided with a plurality of movable louver members,

generally designated 114, or other suitable closure whereby to provide for air communication between the compartments 60a and 60b. The construction and operation of the louvers 114 may be similar to the louvers 88 shown in FIG. 4, although various alternative constructions will be found to be satisfactory, as will be apparent to those skilled in the art;

In operation of the air curtain structure illustrated in FIG. 8, it will be appreciated that when the louvers 114 are disposed in an open configuration, whereby to provide for air flow through the partition assembly 112,

- the structure 10 will operate in the same manner as the structure illustrated in FIG. 2; however, upon closing the louvers 114 so as to block the air flow between the compartments 60a and 60b, the air curtain structure 10 may be operated in a somewhat different manner than the analogous structure shown in FIG. 2. In particular, when the louvers 114 are closed, it is possible to induct air through either of the air inlet assemblies 82 or 84 without requiring that the other of said assemblies 82,

84 be closed. Thus, when it is desired to recirculate the air within the interior of the building 12 and not induct any fresh air through the air inlet assembly 84, said assembly 84 may be left open and through proper energization of the blower mechanism 102 in the compartment 62, air will be inducted through the inlet assembly 82, as indicated by the dotted arrows shown in FIG. 8, which air will thereafter be forced downwardly through the support column 30 and be subsequently discharged through the slot 32 therein. Similarly, if it is desired to induct fresh outside air into the building 12 without recirculating any air already therein, it is merely necessary to close the louvers 114 and energize the blower mechanism 102 in the compartment 58, whereby such air will be inducted through the inlet assembly 84 and will be subsequently forced downwardly through the support column 28 and discharged through the slot 32 therein. Of course, fresh air may be simultaneously inducted and discharged with the induction and recirculation of air within the building 12 by either energizing both of the blower mechanisms 102 or by opening the louvers 114 and operating either or both the blower mechanisms 102, as previously described. Thus, it will be seen that the provision of the partition 112 greatly enhances the variety of applications for the air curtain structure 10 of the present invention, yet does not require any substantial modification in the overall construction or operation thereof.

While it will be apparent that the preferred embodiments illustrated herein are well calculated to fulfill the objects above stated, it will be appreciated that the present invention is susceptible to modification, variation and change without departing from the scope of the invention.

lclaim:

1. In an apparatus for providing an air curtain across an access opening to a work space,

a pair of generally vertically extending discharge ducts arranged adjacent the opposite sides of the opening and having discharge openings for discharging a flow of air at least partially thereacross,

a generally horizontally disposed enclosure extending between the upper ends of said ducts and disposed adjacent the top of said opening, said enclosure including first and second horizontally spaced vertical sides confronting the exterior and interior of the work space, respectively,

first and second air inlets on said first and second.

sides, respectively,

passage defining means within said enclosure defining a first air flow path for communicating air between said first inlet'and one of said discharge ducts, and a second air flow path for communicating air between said second inlet and the other of said discharge ducts, and

at least one heat exchanger disposed generally vertically within said enclosure and extending between said sides generally transversely of one of said flow paths and in heat transfer relationship with air communicated therealong so as to selectively control the temperature of the air drawn into said enclosure through the associated of said inlets preparatory to said air being discharged through the associated of said ducts.

2. An apparatus as set forth in claim 1 which includes blower means for inducting air into said enclosure from said inlets and for forcing said air along said paths toward said discharge ducts.

3. An apparatus as set forth in claim 1 wherein said heat exchanger comprises hot water coil means communicable with a source of hot water and adapted to have air passed therethrough in order to heat said air preparatory to the same being communicated to said discharge ducts.

4. An apparatus as set forth in claim 1 wherein said first air inlet is communicable with a source of fresh outside air.

5. An apparatus as set forth in claim 4 which includes blower means on the opposite side of said heat exchanger from said first air inlet whereby to induct air through said first air inlet and force said air in heat transfer relationship with respect to said heat exchanger.

6.,An apparatus as set forth in claim 1 which includes filter means for filtering air inducted through said first and second air inlets, and wherein said first air inlet is exposed to the exterior of the work space and is adapted to induct fresh outside air into said enclosure, and said second air inlet is exposed to the interior of the work space and is adapted to induct air from the interior of the work space into said enclosure.

7. An apparatus as set forth in claim 6 which includes first and second heat exchanger coil means within said enclosure, each of said coil means extending vertically between said first and second sides and being arranged generally transverse to said air flow paths, and which includes partition means separating said coil means and said flow paths, whereby air inducted through one of said inlets may be communicated in heat transfer relation with one of said coil means and air inducted through the other of said inlets is communicated in heat transfer relation with the other of said coil means.

8. In an apparatus for providing an air curtain across an access opening in a wall or the like separating first and second areas,

a pair of generally vertically disposed discharge ducts arranged one adjacent each side of the access opening and each having an air discharge portion through which air may be directed across said opening,

an enclosure adjacent the top of said opening and extending between the upper ends of said ducts, said enclosure including a pair of vertically extending, horizontally spaced parallel sides defining an air flow passage communicable with said discharge ducts,

a first air inlet in one side of said enclosure for inducting air from one of said areas into said passage,

a second air inlet in the opposite side of said enclosure for inducting air from the other of said areas into said passage, and

a generally vertically oriented heat exchanger located within said enclosure and extending transversely between said sides and arranged in heat transfer relationship with air flowing from at least one of said air inlets to said ducts,

said heat exchanger including means defining a fluid path, a source of fluid communicable with said path, and means for selectively controlling the temperature of said fluid, whereby to control the air flowing in heat transfer relation to said exchanger.

9. An apparatus as set forth in claim 8 which includes blower means for inducting air through said inlets and forcing said air along said air flow passage toward said discharge ducts.

10. An apparatus as set forth in claim 8 which includes first and second heat exchanger coil means communicable with air inducted through said air inlets, and closure means on said first and second air inlets for selectively opening and closing flow paths therethrough.

11. An apparatus as set forth in claim 10 which includes first and second blower means arranged on the opposite sides of said coil means from said first and second air inlets for inducting air through said inlets and drawing said air through the associated of said coil means and then to the associated of said discharge ducts.

12. An apparatus as set forth in claim 11 which includes partition means dividing said passage between said first and second air inlet means, and wherein said partition means includes means for opening and closing an air flow path between said first and second air inlet means.

13. An apparatus as set forth in claim 12 which includes movable louver means on said partition means opening and closing said path.

14. An air curtain structure for providing a flow of air across an access opening to a building or the like and comprising,

an enclosure adjacent the upper end of the opening,

a pair of downwardly extending support columns arranged adjacent the sides of the opening and defining a pair of opposed air discharge slots,

said enclosure being provided with a pair of heat exchanger coil assemblies adapted to condition air preparatory to the same being communicated to the support columns,

at least one air blower mechanism for forcing air in heat transfer relation with the coil assemblies, and

a pair of air inlet assemblies, one of which faces the interior of the building and is adapted to induct air from the interior of the building into the enclosure and the other of which faces the exterior of the building and is adapted to induct fresh outside air from the exterior of the building into the enclosure,

said air inlet assemblies being provided with closure means for selectively opening and closing the same, whereby to permit either the induction of fresh outside air and/or the recirculation of air inside the building through the heat exchanger coil assemblies, and heat exchanger means extending vertically within said enclosure and generally transversely to air flowing between said inlet assemblies and support columns.

15. In an apparatus for providing an air curtain across an access opening in an exterior wall of a work space,

a discharge duct arranged along one side of the opening and having a discharge opening for directing the flow of air across said opening,

an enclosure disposed adjacent said discharge duct and having one side thereof exposed to the interior of the work space and another side thereof exposed tothe exterior of the work space,

a first air inlet in one vertical side of said enclosure facing and communicable with the interior of said work space and a second air inlet in another vertical side of said enclosure facing and communicable with the exterior of said work space,

said enclosure defining a flow path for communicating air from said air inlets toward said discharge duct, and

a generally vertically disposed heat exchanger located within said enclosure and extending between said vertical sides thereof, said heat exchanger including a plurality of fluid coils, means for communicating fluid to said coils and means for selectively controlling the temperature of said fluid and thereby controlling the temperature of the air flowing between said air inlets and said discharge duct in heat transfer relation to said heat exchanger.

16. In an apparatus for providing an air curtain across an access opening in an exterior wall of a work space,

a pair of generally vertically disposed discharge ducts arranged adjacent the opposite sides of said opening and each having an air discharge opening for directing air across said access opening,

an elongated, generally horizontally disposed enclosure having front and rear vertical sides extending between the upper ends of said discharge ducts and located adjacent the top of said opening,

a first air inlet in said rear side of said enclosure communicable with the interior of the work space,

a second air inlet in said front side of said enclosure communicable with the exterior of said work space,

means including said-sides defining a first flow path communicating said first air inlet with one of said discharge ducts and a second flow path communicating said second air inlet with the other of said discharge ducts, and

associated of said discharge ducts flows in heat transfer relationship therewith.

17. The invention as set forth in claim 16 wherein said first and second heat exchanger units each comprises a plurality of fluid coils extending transversely of said enclosure, and which includes a fluid source and means for controlling the temperature of fluid from said source. 

1. In an apparatus for providing an air curtain across an access opening to a work space, a pair of generally vertically extending discharge ducts arranged adjacent the opposite sides of the opening and having discharge openings for discharging a flow of air at least partially thereacross, a generally horizontally disposed enclosure extending between the upper ends of said ducts and disposed adjacent the top of said opening, said enclosure including first and second horizontally spaced vertical sides confronting the exterior and interior of the work space, respectively, first and second air inlets on said first and second sides, respectively, passage defining means within said enclosure defining a first air flow path for communicating air between said first inlet and one of said discharge ducts, and a second air flow path for communicating air between said second inlet and the other of said discharge ducts, and at least one heat exchanger disposed generally vertically within said enclosure and extending between said sides generally transversely of one of said flow paths and in heat transfer relationship with air communicated therealong so as to selectively control the temperature of the air drawn into said enclosure through the associated of said inlets preparatory to said air being discharged through the associated of said ducts.
 1. In an apparatus for providing an air curtain across an access opening to a work space, a pair of generally vertically extending discharge ducts arranged adjacent the opposite sides of the opening and having discharge openings for discharging a flow of air at least partially thereacross, a generally horizontally disposed enclosure extending between the upper ends of said ducts and disposed adjacent the top of said opening, said enclosure including first and second horizontally spaced vertical sides confronting the exterior and interior of the work space, respectively, first and second air inlets on said first and second sides, respectively, passage defining means within said enclosure defining a first air flow path for communicating air between said first inlet and one of said discharge ducts, and a second air flow path for communicating air between said second inlet and the other of said discharge ducts, and at least one heat exchanger disposed generally vertically within said enclosure and extending between said sides generally transversely of one of said flow paths and in heat transfer relationship with air communicated therealong so as to selectively control the temperature of the air drawn into said enclosure through the associated of said inlets preparatory to said air being discharged through the associated of said ducts.
 2. An apparatus as set forth in claim 1 which includes blower means for inducting air into said enclosure from said inlets and for forcing said air along said paths toward said discharge ducts.
 3. An apparatus as set forth in claim 1 wherein said heat exchanger comprises hot water coil means communicable with a source of hot water and adapted to have air passed therethrough in order to heat said air preparatory to the same being communicated to said discharge ducts.
 4. An apparatus as set forth in claim 1 wherein said first air inlet is communicable with a source of fresh outside air.
 5. An apparatus as set forth in claim 4 which includes blower means on the opposite side of said heat exchanger from said first air inlet whereby to induct air through said first air inlet and force said air in heat transfer relationship with respect to said heat exchanger.
 6. An apparatus as set forth in claim 1 which includes filter means for filtering air inducted through said first and second air inlets, and wherein said first air inlet is exposed to the exterior of the work space and is adapted to induct fresh outside air into said enclosure, and said second air inlet is exposed to the interior of the work space and is adapted to induct air from the interior of the work space into said enclosure.
 7. An apparatus as set forth in claim 6 which includes first and second heat exchanger coil means within said enclosure, each of said coil means extending vertically between said first and second sides and being arranged generaLly transverse to said air flow paths, and which includes partition means separating said coil means and said flow paths, whereby air inducted through one of said inlets may be communicated in heat transfer relation with one of said coil means and air inducted through the other of said inlets is communicated in heat transfer relation with the other of said coil means.
 8. In an apparatus for providing an air curtain across an access opening in a wall or the like separating first and second areas, a pair of generally vertically disposed discharge ducts arranged one adjacent each side of the access opening and each having an air discharge portion through which air may be directed across said opening, an enclosure adjacent the top of said opening and extending between the upper ends of said ducts, said enclosure including a pair of vertically extending, horizontally spaced parallel sides defining an air flow passage communicable with said discharge ducts, a first air inlet in one side of said enclosure for inducting air from one of said areas into said passage, a second air inlet in the opposite side of said enclosure for inducting air from the other of said areas into said passage, and a generally vertically oriented heat exchanger located within said enclosure and extending transversely between said sides and arranged in heat transfer relationship with air flowing from at least one of said air inlets to said ducts, said heat exchanger including means defining a fluid path, a source of fluid communicable with said path, and means for selectively controlling the temperature of said fluid, whereby to control the air flowing in heat transfer relation to said exchanger.
 9. An apparatus as set forth in claim 8 which includes blower means for inducting air through said inlets and forcing said air along said air flow passage toward said discharge ducts.
 10. An apparatus as set forth in claim 8 which includes first and second heat exchanger coil means communicable with air inducted through said air inlets, and closure means on said first and second air inlets for selectively opening and closing flow paths therethrough.
 11. An apparatus as set forth in claim 10 which includes first and second blower means arranged on the opposite sides of said coil means from said first and second air inlets for inducting air through said inlets and drawing said air through the associated of said coil means and then to the associated of said discharge ducts.
 12. An apparatus as set forth in claim 11 which includes partition means dividing said passage between said first and second air inlet means, and wherein said partition means includes means for opening and closing an air flow path between said first and second air inlet means.
 13. An apparatus as set forth in claim 12 which includes movable louver means on said partition means opening and closing said path.
 14. An air curtain structure for providing a flow of air across an access opening to a building or the like and comprising, an enclosure adjacent the upper end of the opening, a pair of downwardly extending support columns arranged adjacent the sides of the opening and defining a pair of opposed air discharge slots, said enclosure being provided with a pair of heat exchanger coil assemblies adapted to condition air preparatory to the same being communicated to the support columns, at least one air blower mechanism for forcing air in heat transfer relation with the coil assemblies, and a pair of air inlet assemblies, one of which faces the interior of the building and is adapted to induct air from the interior of the building into the enclosure and the other of which faces the exterior of the building and is adapted to induct fresh outside air from the exterior of the building into the enclosure, said air inlet assemblies being provided with closure means for selectively opening and closing the same, whereby to permit either the induction of fresh outside air and/or tHe recirculation of air inside the building through the heat exchanger coil assemblies, and heat exchanger means extending vertically within said enclosure and generally transversely to air flowing between said inlet assemblies and support columns.
 15. In an apparatus for providing an air curtain across an access opening in an exterior wall of a work space, a discharge duct arranged along one side of the opening and having a discharge opening for directing the flow of air across said opening, an enclosure disposed adjacent said discharge duct and having one side thereof exposed to the interior of the work space and another side thereof exposed to the exterior of the work space, a first air inlet in one vertical side of said enclosure facing and communicable with the interior of said work space and a second air inlet in another vertical side of said enclosure facing and communicable with the exterior of said work space, said enclosure defining a flow path for communicating air from said air inlets toward said discharge duct, and a generally vertically disposed heat exchanger located within said enclosure and extending between said vertical sides thereof, said heat exchanger including a plurality of fluid coils, means for communicating fluid to said coils and means for selectively controlling the temperature of said fluid and thereby controlling the temperature of the air flowing between said air inlets and said discharge duct in heat transfer relation to said heat exchanger.
 16. In an apparatus for providing an air curtain across an access opening in an exterior wall of a work space, a pair of generally vertically disposed discharge ducts arranged adjacent the opposite sides of said opening and each having an air discharge opening for directing air across said access opening, an elongated, generally horizontally disposed enclosure having front and rear vertical sides extending between the upper ends of said discharge ducts and located adjacent the top of said opening, a first air inlet in said rear side of said enclosure communicable with the interior of the work space, a second air inlet in said front side of said enclosure communicable with the exterior of said work space, means including said sides defining a first flow path communicating said first air inlet with one of said discharge ducts and a second flow path communicating said second air inlet with the other of said discharge ducts, and first and second heat exchanger units disposed generally vertically within said enclosure and extending generally transversely between said front and rear sides thereof, said first heat exchanger unit extending across said first flow path whereby air flow from said first inlet toward the associated of said discharge ducts flows in heat transfer relation therewith, and said second heat exchanger unit extending across said second flow path so that air flowing from said second air inlet toward the associated of said discharge ducts flows in heat transfer relationship therewith. 